[mirror_ubuntu-artful-kernel.git] / fs / btrfs / ulist.h

/*
 * Copyright (C) 2011 STRATO AG
 * written by Arne Jansen <sensille@gmx.net>
 * Distributed under the GNU GPL license version 2.
 *
 */

#ifndef __ULIST__
#define __ULIST__

/*
 * ulist is a generic data structure to hold a collection of unique u64
 * values. The only operations it supports is adding to the list and
 * enumerating it.
 * It is possible to store an auxiliary value along with the key.
 *
 * The implementation is preliminary and can probably be sped up
 * significantly. A first step would be to store the values in an rbtree
 * as soon as ULIST_SIZE is exceeded.
 */

/*
 * number of elements statically allocated inside struct ulist
 */
#define ULIST_SIZE 16

/*
 * element of the list
 */
struct ulist_node {
	u64 val;		/* value to store */
	unsigned long aux;	/* auxiliary value saved along with the val */
};

struct ulist {
	/*
	 * number of elements stored in list
	 */
	unsigned long nnodes;

	/*
	 * number of nodes we already have room for
	 */
	unsigned long nodes_alloced;

	/*
	 * pointer to the array storing the elements. The first ULIST_SIZE
	 * elements are stored inline. In this case the it points to int_nodes.
	 * After exceeding ULIST_SIZE, dynamic memory is allocated.
	 */
	struct ulist_node *nodes;

	/*
	 * inline storage space for the first ULIST_SIZE entries
	 */
	struct ulist_node int_nodes[ULIST_SIZE];
};

void ulist_init(struct ulist *ulist);
void ulist_fini(struct ulist *ulist);
void ulist_reinit(struct ulist *ulist);
struct ulist *ulist_alloc(unsigned long gfp_mask);
void ulist_free(struct ulist *ulist);
int ulist_add(struct ulist *ulist, u64 val, unsigned long aux,
	      unsigned long gfp_mask);
struct ulist_node *ulist_next(struct ulist *ulist, struct ulist_node *prev);

#endif
Commit	Line	Data
da5c8135 AJ	1	/*
	2	* Copyright (C) 2011 STRATO AG
	3	* written by Arne Jansen <sensille@gmx.net>
	4	* Distributed under the GNU GPL license version 2.
	5	*
	6	*/
	7
	8	#ifndef __ULIST__
	9	#define __ULIST__
	10
	11	/*
	12	* ulist is a generic data structure to hold a collection of unique u64
	13	* values. The only operations it supports is adding to the list and
	14	* enumerating it.
	15	* It is possible to store an auxiliary value along with the key.
	16	*
	17	* The implementation is preliminary and can probably be sped up
	18	* significantly. A first step would be to store the values in an rbtree
	19	* as soon as ULIST_SIZE is exceeded.
	20	*/
	21
	22	/*
	23	* number of elements statically allocated inside struct ulist
	24	*/
	25	#define ULIST_SIZE 16
	26
	27	/*
	28	* element of the list
	29	*/
	30	struct ulist_node {
	31	u64 val; /* value to store */
	32	unsigned long aux; /* auxiliary value saved along with the val */
	33	};
	34
	35	struct ulist {
	36	/*
	37	* number of elements stored in list
	38	*/
	39	unsigned long nnodes;
	40
	41	/*
	42	* number of nodes we already have room for
	43	*/
	44	unsigned long nodes_alloced;
	45
	46	/*
	47	* pointer to the array storing the elements. The first ULIST_SIZE
	48	* elements are stored inline. In this case the it points to int_nodes.
	49	* After exceeding ULIST_SIZE, dynamic memory is allocated.
	50	*/
	51	struct ulist_node *nodes;
	52
	53	/*
	54	* inline storage space for the first ULIST_SIZE entries
	55	*/
	56	struct ulist_node int_nodes[ULIST_SIZE];
	57	};
	58
	59	void ulist_init(struct ulist *ulist);
	60	void ulist_fini(struct ulist *ulist);
	61	void ulist_reinit(struct ulist *ulist);
	62	struct ulist *ulist_alloc(unsigned long gfp_mask);
	63	void ulist_free(struct ulist *ulist);
	64	int ulist_add(struct ulist *ulist, u64 val, unsigned long aux,
65	unsigned long gfp_mask);
66	struct ulist_node ulist_next(struct ulist ulist, struct ulist_node *prev);
67
68	#endif